Method and apparatus for degreasing a metal part

ABSTRACT

Disclosed is a process of recycling and reusing an aqueous degreasing solution for further use as a component of a coolant solution which is itself recycled and reused in metal cutting machines. Also disclosed is a method of degreasing parts, and a degreasing apparatus which is controlled such that an appropriate amount of the aqueous degreasing solution is introduced into the coolant solution. Finally, disclosed herein is a method and system for preparing a coolant in which an aqueous degreasing solution is further utilized as a feeder solution for a coolant solution, with the resulting solution being able to be separated into its component parts and reused in the cutting and cleaning of metals to form metal parts.

RELATED APPLICATIONS

[0001] This application is a divisional of co-pending U.S. patentapplication Ser. No. 09/657,680 filed on Sep. 8, 2000, which is adivisional of U.S. patent application Ser. No. 09/408,712 filed on Sep.30, 1999, which is a divisional of U.S. patent application Ser. No.09/135,491 filed on Aug. 17, 1998 (now U.S. Pat. No. 5,983,910 issuedNov. 16, 1999), which is a divisional of U.S. patent application Ser.No. 08/739,613 filed Oct. 30, 1996 (now U.S. Pat. No. 5,795,400 issuedAug. 18, 1998), which is a file wrapper continuation of U.S. patentapplication Ser. No. 08/243,574 filed on May 16, 1994, and are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

[0002] I. Field of the Invention

[0003] The present invention relates generally to a method and apparatusof recycling and reusing an aqueous degreasing solution for further useas a component of a cooling solution which is itself recycled and reusedin metal cutting machines.

[0004] II. Description of the Prior Art

[0005] The metal working industry is one of the most heavily regulatedindustries. One area of this industry that is being scrutinized is thedegreasing operation. That is, the metal parts coming out of the cuttingmachines are covered in metal working fluids and residual lubricants.This occurs because oils are used as lubricants as the raw materialmetal is cut to form the finished part. Traditionally, heavy,non-soluble oils were used as lubricants. Vapor phase degreasing was themethod of choice for the removal of non-soluble oils from the finishedparts. Popular vapor phase degreasers are halogenated solvents such asFreon 113; 1, 1, 1-trichloroethane, trichloroethene, methylene chloride,and tetrachloroethene. These first two are suspected ozone depleters,and the remaining three are suspected carcinogens.

[0006] With the introduction of lighter, soluble oils as lubricants inthe metal cutting industry, the use of aqueous phase degreasers became apossibility. However, because of the fear of corrosion and also theexpense of converting from a vapor to an aqueous phase degreasingprocess, vapor phase degreasing remained the method of choice.

[0007] With the advent of new and more stringent environmentalregulations, vapor phase degreasing is becoming a disfavored method ofcleaning metal parts. This is so because two of the more common vaporphase degreasers are Freon 113 and 1, 1, 1-trichloroethane, substancessuspected to deplete the earth's ozone layer. In 1990, Congress passedmore stringent laws providing that all parts manufactured by a processinvolving an ozone depleting substance must be labeled to that effect.This has caused many companies to look to aqueous phase degreasing.

[0008] Despite its environmental advantages over vapor phase degreasingwith respect to ozone depletion, if not managed properly, aqueous phasedegreasing can create environmental problems of its own. The problem ofwaste water and water pollution is of tremendous concern. As a result,it would be highly desirable for the metal working industry to utilizean aqueous phase degreasing procedure in which the aqueous degreasingsolution could be recycled and reused as feeder solution for a metalcutting machine coolant, which is itself recyclable and reusable.Tremendous benefits could be reaped by minimizing worker exposure toharmful substances, as well as reducing or eliminating hazardous wastestreams.

SUMMARY OF THE PRESENT INVENTION

[0009] A method and apparatus for cooling and washing metal parts whichincludes washing the metal parts in a degreasing solution, mixing theused degreasing solution with a coolant solution and using the mixtureas a coolant in a metal forming operation is disclosed. In this way thewash solution is recycled and reused. The apparatus includes a washstation, rinse station and drying station through which the parts aremoved sequentially. The apparatus further includes a counterflow offluid beginning in the rinse tank and moving downstream through the washtank at a predetermined rate. The used wash solution is collected forrecycling. Also disclosed is a skimming operation and a method ofseparating degreasing solution from the coolant mixture for recycling inthe degreasing system. The method includes using ultrafiltration andprecipitation to separate the components.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A better understanding of the present invention will be had uponreference to the following detailed description, when read inconjunction with the accompanying drawings, wherein like referencenumerals refer to parts throughout the several views, and in which:

[0011]FIG. 1 is a block diagram setting forth the steps in the processof recycling and reusing an aqueous degreasing solution into a coolantsolution;

[0012]FIG. 2 is a block diagram in which an ultrafiltration step hasbeen added to the recycling process;

[0013]FIG. 3 is a perspective view of the degreasing system inaccordance with the invention;

[0014]FIG. 3A is a schematic view of the degreasing system according tothe invention;

[0015]FIG. 4 is a cross-sectional view of a skimmer in accordance withthe invention;

[0016]FIG. 5 is a cross-sectional view of a wash bath in accordance withthe invention;

[0017]FIG. 6 is a partial perspective view of a portion of a carrier andbath in accordance with the invention; and

[0018]FIG. 7 is a cross-sectional view of a carrier showing baskets inaccordance with the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION

[0019] With reference first to FIG. 1, a block diagram of a process inwhich used degreasing solution is recycled and reused in a coolantsolution for metal cutting machines, which is itself recycled andreused, is there shown. Raw metal 10 is sent to a cutting machine 12 tobe cut into formed metal parts 14. The formed part 14 exits the cuttingmachine 12 on a conveyor belt (not shown). Metal shavings 16 accumulatedduring the cutting process exit off a second conveyor belt (not shown).Both the formed metal parts 14 and the metal shavings 16 are covered inlubricating oils 18 and coolant solution 20 as a part of the metalcutting process.

[0020] The coolant solution 20 that is utilized in the cutting machines12 contains approximately 2-7% by volume water miscible cutting andgrinding fluid concentrate 28 (Masterline Brass Cut available fromMaster Chemical Corporation in Perrysburg, Ohio), approximately 1-2%water miscible washing compound concentrate 30 (Masterline Brass Cleanavailable from Master Chemical Corporation in Perrysburg, Ohio), and thebalance purified water. The water miscible washing compound concentrate30 causes excessive foaming within the cutting machine 12 at aconcentration above 2%. The water miscible cutting and grinding fluidconcentrate 28 and the water miscible washing compound concentrate 30are chemically compatible solutions built from compatible chemicalbuilding blocks. These building blocks comprise a compound selected fromthe group consisting of an amine carboxylate, a nonionic surfactant, anantioxidant, a petroleum oil, a petroleum sulfonate, an aromaticalcohol, a glycol ether, a carboxylic acid, water, and mixtures thereof.All of the water miscible washing compound concentrate 30 that is usedin the coolant solution 20 is taken from the aqueous phase degreasingsystem 32.

[0021] In one embodiment, the water miscible washing compoundconcentrate 30 comprises 40-50% by weight amine carboxylate, 10-20%nonionic surfactant, 1-10% pine oil, less than 1% glycol, less than 1%substituted indole, and water. The water miscible cutting and grindingfluid concentrate 28 comprises 60-70% by weight petroleum oil, 20-30%petroleum sulfonate, 1-10% nonionic surfactant, 1-10% aromatic alcohol,1-10% propylene glycol ether, less than 1% propylene glycol, and water.

[0022] In the course of running the metal cutting machine 12, thecoolant solution 20 becomes mixed with tramp oils, dirt, and metalshavings 16. This dirty coolant 22 is collected from the cuttingmachines 12 into a holding tank 24. At the same time, the metal shavings16 coming off the conveyor are collected and sent through a squeezer 26to squeeze off the dirty coolant 22. This dirty coolant 22 from themetal shavings 16 is also sent to the holding tank 24.

[0023] The metal parts 14 covered with oils and coolant solution 20 aretaken from the cutting machines 12 and sent through an aqueous phasedegreasing system 32 to be discussed more fully below. The parts 14 areimmersed in a series of wash baths or tanks 34 at approximately 160° F.containing approximately 2-6% of the water miscible washing compoundconcentrate 30 and the balance chemically purified water 31, forming anaqueous degreasing or wash solution 35. The parts are then immersed in aseries of purified water rinse baths 36, sent through a dryer 38, andthen sent off for further use in manufacturing operations or as finishedparts 40. Oils coming off the parts 14 during washing are skimmed offthe tops of the wash baths 34, and the used aqueous degreasing solution42 is collected off of a wash bath 34 and sent to the dirty coolantholding tank 24 where it becomes a feeder solution for the coolantsolution 20. The entire aqueous phase degreasing system 32 is controlledso that the used aqueous degreasing solution 42 can be collected from awash bath 34 at a rate sufficient to permit total use of the usedaqueous degreasing solution 42 in the coolant solution 20. In apreferred embodiment, the used aqueous degreasing solution 42 iscollected from a single wash bath 32 at a rate of ½gallon/minute, with100% of the used aqueous degreasing solution 42 being recycled andreused as a feeder solution for the dirty coolant 22. None of the usedaqueous degreasing solution 42 is sent out as waste.

[0024] The dirty coolant 22 which has been gathered into a holding tank24 from the metal cutting machines 12, the squeezed metal shavings 16,and the wash baths 34 of the aqueous phase degreasing system 32 is thensent through a high speed disc bowl centrifuge 44 where thecontaminating tramp oils and other contaminants are “spun out.” Thiscleaned and recycled coolant solution 20 is then sent to a clean coolantreservoir 48 (FIG. 2) where the proper concentrations of water and watermiscible washing compound concentrate 30 are maintained prior tointroduction of the clean coolant solution 20 back into the metalcutting machines 12.

[0025] Because all of the used aqueous degreasing solution 42 from theaqueous phase degreasing system 32 is being reused as feeder solutionfor the dirty coolant 22, problems can arise with the cutting machines12 if the level of water miscible washing compound concentrate 30 fromthe used aqueous degreasing solution 42 becomes too high in the coolantsolution 20 introduced back into the cutting machines 12. One problemthat results is foaming within the metal cutting machines 12, and theother problem that results is elevated concentrations of the metalsbeing machined in the coolant solution 20. The metal contaminants buildup in the used aqueous degreasing solution 42 as a natural outcome ofcutting and washing the metal parts 14.

[0026] The used aqueous degreasing solution 42 (along with the metalcontaminants) is then added into the holding tank 24 along with theother dirty coolant 22 that has been collected. Centrifugation 44 onlyremoves dirt and tramp oil from the dirty coolant 22. One way to controlthe concentrations of metal contaminants and water miscible washingcompound concentrate 30 in the coolant solution 20 that is sent back tothe cutting machines 12 is through ultrafiltration 50.

[0027] With reference now to FIG. 2, an ultrafiltration step 50 can beadded to the overall process of recycling and reusing an aqueousdegreasing solution 35 as a feeder solution for a dirty coolant solution22 which is also recycled and reused. After the dirty coolant iscentrifuged 44, but before it is sent back into the cutting machines 12a portion of the clean coolant 20 is sent through an ultrafiltrationunit in which the retentate 52 contains primarily water miscible cuttingand grinding fluid concentrate 28, and the permeate 54 containsprimarily water, metal contaminants, and water miscible washing compoundconcentrate 30. The metal contaminants come through the ultrafiltrationunit 50 in direct proportion to the water miscible washing compoundconcentrate 30. Removal of an amount of coolant 20 necessary to preventbuildup of metal contaminants and washing compound concentrate 30, andto maintain an equilibrium in the coolant 20 for passage through theultrafiltration unit 50 is effective in keeping the concentrations ofheavy metals and water miscible washing compound concentrate 30 undercontrol before sending the clean coolant 20 back into the cuttingmachines 12. In the present embodiment as little as 1% of the systemvolume of coolant 20 is removed per day for passage through theultrafiltration unit 50.

[0028] The permeate 54 containing water, water miscible washing compoundconcentrate 30, and metal contaminants can then be further purified toremove the metal contaminants. Once separated by ultrafiltration 50 boththe retentate 52 and the permeate 54 (absent the metal contaminants) canbe reused and recycled back into the cutting machines 12 or wash baths34 respectively, or sent to waste treatment. The additional step ofultrafiltration 50 allows for the levels of water miscible washingcompound concentrate 30 and metal contaminants in the clean coolantsolution 20 to be better controlled before the clean coolant 20 goesback into the cutting machines 12, without the necessity of decantingthe coolant solution 20 several times a year to keep the coolantsolution 20 properly balanced. Alternatively, in the present embodiment,the dirty coolant 22 can be removed from the dirty coolant holding tank24 and sent through the ultrafiltration unit 50.

[0029] As best shown in FIG. 3 and 3A, the degreasing system 32 includesan automated apparatus for removing coolant solution from the metalparts 14. The metal parts 14 are moved in a parts carrier 102 by a pairof hoists 140, 141 sequentially through a series of stations including aloading/unloading station 104, a wash station 106, a rinse station 108,and then to a drying station 110. The wash station 106 includes a seriesof three wash baths 34 and skimmers 136 which skim oil from a washsolution. The rinse station 108 includes four rinse baths 36.

[0030] The degreasing system 32 utilizes a flow of liquid which beginswith chemically purified water 31 from a water supply 33 which isintroduced at the rinse station 108 and flows downstream through thewash station 106 where the washing compound concentrate 30 is added toform a wash solution 35. Thus, the metal parts 14 are moved upstreamthrough increasingly clean liquid during the degreasing operation.

[0031] The loading station 104 consists of a conveyor 114 which isdriven by an electric motor (not shown). Operation of the motor iscontrolled by a central processing unit 116 to move the parts carrier102 between a loading position (shown in FIG. 3) and a staging position.The parts 14 are delivered in metal baskets 118 (shown in FIG. 7) to theloading station 104 from the cutting machine 12. The metal baskets 118have openings in all sides to permit the wash solution and rinse waterto pass through and drain from the baskets 118.

[0032] As shown in FIGS. 3 and 7, the carrier 102 includes a drum 120which is mounted for axial rotation in a frame 122. The drum 120 isformed of a metal lattice which permits liquid to pass through to thebaskets 118 and parts 14. The drum 120 has pairs of jaws 121 which moveapart to permit access to an interior compartment formed to hold stacksof the metal baskets 118 containing the parts 14. The jaws 121 are movedtogether to lock the baskets 118 in position within the carrier 102. Theframe 122 includes an elongated bridge 124 which extends between a pairof vertical end panels 126. The panels 126 have flat bottom surfaces andare dimensioned to keep the bridge above the surface of the liquid inthe wash station 106 and rinse station 108. The drum 120 is mountedbetween the end panels 126 beneath the bridge 124. A D/C motor 130 ismounted to a top surface of the bridge 124. The motor 130 is connectedin a suitable manner such as a belt or drive rods and gear mechanisms toselectively rotate the drum 120.

[0033] As best shown in FIG. 6, three metal L-shaped arms 132 extendoutwardly from each of the end panels 126 to provide electrical currentfor the D/C motor. The arms 132 are spring biased to permit movementalong a vertical axis and are positioned so as to contact electricalcontacts 134 positioned adjacent to each bath 34, 36. As will bedescribed below, the motor 130 may be selectively energized to rotatethe drum 120 when the carrier 102 is immersed in the baths 34, 36 orsuspended by either of the two hoists 140, 141. A pair of lifting pegs142 are positioned on each end panel 126, one on either side of the arms132 for engagement with lift hooks of the hoists 140, 141. The baskets118 are loaded into the parts carrier 102. After the parts carrier 102is loaded, the conveyor 114 moves the carrier 102 to a staging positionadjacent the washing station 106.

[0034] As best shown in FIGS. 3 and 5, the wash station 106 includesthree identical baths 34. Each of the baths 34 is rectangular, having apair of sides 146, a pair of ends 148, 150 and a bottom 152. The bottom152 of each bath 34 has a rectangular channel 154 formed along one sidefor housing an auger 156. The auger 156 is turned by an electric motor(not shown). The bottom 152 has a central portion 158 which slopesdownwardly towards the channel 154 to deliver any metal flakes or debrisfrom the parts 14 into the channel 154. The auger 156 carries the debristhrough the channel 154 to a drain 160 having a trap 161 for capturingthe debris. The trap 161 is a removable basket for disposing of thedebris.

[0035] As shown in FIGS. 3, 4 and 6, a steam pipe 162 delivers steam tothe sides 146. A conduit 164 delivers the steam from a boiler 166 to aheating coil 167 positioned beneath each tank 34, 36 to heat liquid inthe tanks 34, 36. The water is heated to approximately 160° F.Ultrasonic wave generators 168 are mounted between the sides 146 of thebaths to produce waves which move the liquid between the parts 14 in thebaskets 118 to permit the fluid in the tanks 34, 36 to pass fully aroundthe parts 14. This facilitates cleaning of the parts 14 and removal ofresidual debris. The ultrasonic generators 168 may be of anyconventional type.

[0036] As shown in FIGS. 3 and 5, a horizontally aligned manifold 169having a number of jets 170 is mounted near the top of each tank 34, 36.The liquid is sprayed through the jets 170 into the tank 34, 36. Thewashing solution 35 is delivered to the manifold 169 by a pump 172 andinflow conduit 174 from an associated skimmer 136. The washing solutionis permitted to flow over a weir 174 into a collector 175 located at oneend 148 of the tank 34, 36 from which it is gravity fed through anoutflow conduit 176 back to the skimmer 136.

[0037] As shown in FIGS. 3 and 4, each of the skimmers 136 is arectangular tank having a main chamber 178, an intermediate chamber 180and a collector 182. The main chamber 178 is defined by a pair of sidewalls 184, an outer end wall 186 and an interior wall 188 which extendstowards an opening 190 at the bottom of the tank. The outflow conduit176 delivers fluid from the baths through a series of large apertures192. The fluid is delivered by gravity into the main chamber 178 and isallowed to flow into the tank through the apertures 192 below a baffle193 to prevent turbulence so that any tramp oil in the liquid will riseto the surface of the liquid of the main chamber 178 where it will floatto be collected by a skimming device. The skimming device may be of anysuitable type for removing oil. It may be performed by hand or amechanical device as known in the art and may be used to siphon oil fromthe top of the main chamber 178 and delivered by a conduit 196 to areservoir. The liquid is circulated through a filter 197 to removeparticulate matter from the liquid.

[0038] The liquid flows from the main chamber 178 through the opening190 into the intermediate chamber 180 formed between the interior wall188 and a primary weir 198 which is lower than the interior wall 188.The liquid (shown by arrow A) is permitted to cascade over the weir 198into the collector 182 from which it is delivered to the inflow conduit174 and pump 172 for delivery to an associated bath 34, 36. A secondaryweir 200 is formed in each side wall 184 of the collector 182 betweencollectors of adjacent skimmers 136 to permit a portion of the liquid topass downstream to the collector 182 of the adjacent skimmer 136 (shownby arrow B). Thus, there is a downstream counterflow from 136 d to 136 cto 136 b and 136 a as shown in FIG. 3A. When the rinse water flows toskimmer 136 c it is mixed with the aqueous degreasing solution 35, fromwash bath 34 c. The wash solution is, thus, composed of the rinse waterand approximately 2 to 7% and preferably 3 to 4% of the washing compoundconcentrate 30. The concentration of washing compound concentrate 30 ismonitored and controlled in each wash bath 34 on a daily basis. It hasbeen found to be advantageous to maintain the concentration of the firsttwo baths 34 a, 34 c that the parts 14 enter at 4%, and theconcentration of the third bath 34 c at 3%.

[0039] As shown in FIG. 3A, the wash solution 35 is delivered from thewash bath 34 c to a skimmer 136 c and then to the skimmer 136 b. Whereit is recirculated to wash bath 34 b, the wash solution continuesdownstream to skimmer 136 a and to the first wash bath 34 a. The usedaqueous dispensing solution 42 is delivered through a conduit 202 fromthe skimmer 136 a to the dirty coolant tank 24 for use as feedstock inthe coolant solution 20.

[0040] The rinse station 108 includes four baths 36, one bath 36 isseparated from the other rinse baths by a holding table 204. Each of therinse baths 36 is generally rectangular shaped, having the samedimensions as the wash baths 34. However, the rinse tanks 36 do notinclude a channel 154 and auger 156 at the bottom as do the wash tanks34. Steam is delivered from the conduit 164 to the bottom of the tanks136 in order to heat the rinse water 31. A suitable temperature isapproximately 155° F. A weir 208 is formed at one end to permit therinse water 31 to flow from the bath 36 into a collector 210 from whichit is delivered by a conduit 212 and pump 214 to the manifold 169 havingjets 170 to the downstream tank. The rinse water 31 is introduced fromthe water supply 33 through a flow regulator (not shown) into the fourthrinse bath 36 at a rate of between 0.1 and 1.0 gallon per minute. Therate in the preferred embodiment is 1.0 gallon per minute. However, therate of flow of liquid through the system decreases to approximately 0.5gpm because of evaporation from the baths 34, 36. Thus, the flow rate ofliquid is lower in each downstream bath 34, 36.

[0041] As described above, the rinse water 31 cascades downstreamthrough each of the four rinse baths 36, weirs 208 and collector 210 tothe most upstream skimmer 136 where it is then introduced into the thirdor most upstream wash bath where it is mixed with the washing compoundconcentrate 30.

[0042] As shown in FIGS. 3, 3A and 5, the drying station 110 includesthree rectangular drying chambers 213 having the same dimensions as thewash and rinse baths 34, 36. The drying chambers 213 are heated by aheating coil 167 connected to the conduit 164 to receive steam from theboiler 166. The carrier 102 may be thus placed in a chamber 213 andreceive heat from the coil 167 to dry the parts 14 inside the drum 120.

[0043] In the event that the degreasing system 32 needs servicing, therinse water 31 and washing solution 35 may be pumped into two tanks 214,215 for storage during service.

[0044] The two hoists 140, 141 each run on a pair of overhead rails 216.The operation of the hoists 140, 141 is controlled by the CPU 116 whichboth controls the movement of carriages 218 along the rails 216 andoperates chains 222 to raise and lower a lifting plate 220. As shown inFIGS. 3 and 6, each of the lift plates 220 has a pair of V-shapedreceptacles 224 which extend inwardly. The receptacles 224 are spacedapart and positioned to receive the lifting pegs 142 of the carrier 102.Electrical contacts are provided on the carriage 218 to connect with thearms 132 on the carrier 102 to power the electric motor 130 to rotatethe drum 120. The hoists 140, 141 are operable to raise and lower thecarrier 102 to and from the baths 34, 36 and to rotate the drum 20 whenthe carriers 102 are in a raised position. The first of the hoists 140is a wash hoist movable between the staging area of the loading station104 and the holding station 204. The rinse hoist 141 moves between thefirst rinse bath and the drying station 110.

Operation

[0045] Parts 14 are delivered to a carrier 102 at the loading station104 where the baskets 118 are loaded into the drum 120. After beingloaded, the jaws 121 of the drum 120 are closed and the carrier 102 ismoved along the conveyor 114 to the staging area. The carrier 102 isthen lifted by the wash hoist 140 and delivered to the first wash bath34 a. The wash bath 34 a (FIG. 3A) contains a washing solution 35 whichis heated to a temperature of approximately 160°. The parts 14 aresubjected to ultrasonic agitation and may be rotated within the bath 34by turning the drum 120. After approximately one minute in the firstbath 34 a, the carrier 102 is lifted by the wash hoist 140 and moved tothe second and third wash baths 34 b and 34 c. The carrier 102 remainsin each bath 34 for approximately one minute before it is moved on tothe subsequent bath 34. After passing through the third wash bath 34,the carrier is lifted by the wash hoist 140 and deposited at the holdingstation 204.

[0046] The rinse hoist 141 then lifts the carrier 102 into the first ofthe rinse baths 36. The carrier 102 is then subsequently positioned inthe second, third, and fourth rinse baths 36. The carrier 102 is held ineach bath 36 for approximately 15 to 20 seconds. After completing thefour rinse baths 36, the rinse hoist 141 moves the carrier 102 to one ofthe drying chambers 213 while the hoists 140, 141 move other carriers102 through the rinse and wash baths 34, 36. The carrier 102 ispermitted to remain in the drying chamber 213 nearly three full wash andrinse cycles, or approximately 15 minutes. After the carrier 102 hascompleted a drying period, it is removed from the drying chamber 213 bythe rinse hoist 141 and is returned to the holding station 204. The washhoist 140 then moves the carrier 102 to the loading area of the loadingstation 104 where the baskets 118 are unloaded. The timing of themovement of the carriers 102 may be programmed such that the carriers102 are being continuously and progressively moved through the variousbaths 34, 36 and returned to the loading station 104. The movement ofthe carriers through the degreasing system 32 is controlled by the CPU116.

[0047] When fully lifted, the drum 120 of the carrier 102 may be rotatedto drain the wash solution 35 or rinse water 31 from the drum 120 beforemoving on to the next bath 34, 36. However, if the parts 14 are requiredto have a smooth finish, then the drum 120 is not rotated. Additionally,the rotation of the drum 120 can be controlled to provide either acontinuous rotation or a staggered rotation where the drum 120 moves 90°and is held for a period of time before rotating another 90°. One of thearms 132 provides electrical contact for continuous rotation, a secondfor staggered and a third is a ground.

[0048] The present invention, therefore, provides for a coolant andaqueous degreasing reclamation process for the metal finishing industryin which the used aqueous degreasing solution is recycled and reusedinto the coolant solution which is itself recycled and reused. As aresult, the use of ozone depleting or carcinogenic substances is avoidedand the need for sending used solutions into waste water is greatlydiminished. Having described my invention, many modifications theretowill become apparent to those skilled in the art to which it pertainswithout deviation from the spirit of the invention as defined by thescope of the appended claims.

We claim:
 1. An apparatus for degreasing metal parts comprising: atleast one wash tank having a supply of degreasing solution; at least onerinse tank having rinse water therein; means for delivering a flow ofrinse water from said rinse tank to said wash tank; means for skimmingoil from wash tank; and means for delivering a flow of used degreasingsolution from said at least one wash tank to a tank.
 2. A system forcooling a part formed in a metal forming machine, said systemcomprising: means for delivering a coolant fluid used in said metalforming machine to a tank; means for washing coolant fluid from saidmetal parts with a mixture of washing compound and rinse water to form aused degreasing solution; means for delivering said mixture to said tankfrom said means for washing metal parts to said tank, said useddegreasing solution being mixed with said coolant for reuse in saidmetal forming machine; and means for delivering liquid in said tank tosaid metal forming machine.
 3. The system of claim 2 further comprisinga centrifuge for removing contaminants from said liquid in said tank. 4.The system of claim 2 wherein said coolant comprises water misciblecutting fluid.
 5. The system of claim 2 wherein said washing compoundcomprises a water miscible washing compound.
 6. A method of degreasingmetal parts formed in a metal forming machine, said method comprising:forming a plurality of wash tanks, each having a washing compoundtherein; delivering a flow of rinse water to an upstream tank of saidplurality of wash tanks; passing a flow of a mixture of said rinse waterand said washing compound to a downstream tank of said plurality of washtanks; passing work pieces from said downstream tank sequentiallythrough said plurality of wash tanks to said upstream tank; removingused degreasing solution from said downstream tank.
 7. The method ofclaim 6 wherein said removing step includes removing said useddegreasing solution at a first predetermined flow rate.
 8. The method ofclaim 6 wherein said removing step includes the step of delivering saidrinse water at a second predetermined flow rate which is proportioned tosaid first predetermined flow rate.
 9. An apparatus for degreasing metalparts comprising: a plurality of wash tanks containing a washingcompound; at least one rinse tank having rinse water therein; means fordelivering a flow of rinse water to an upstream one of said plurality ofwash tanks; means for producing a flow of liquid from said upstream tankthrough said plurality of wash tanks to a downstream tank; and means forsequentially delivering said metal parts through said wash tankssequentially from said downstream tank to said upstream tank.
 10. Theapparatus of claim 9 further comprising means for skimming coolant fromsaid wash tanks.
 11. The apparatus of claim 9 further comprising meansfor controlling the flow rate of liquid through said wash tanks.
 12. Theapparatus of claim 10 wherein said means for delivering comprises acarrier having means to rotate said parts within said plurality of washtanks.
 13. The apparatus of claim 10 wherein said coolant compriseswater miscible cutting fluid.
 14. The apparatus of claim 9 wherein saidwashing compound comprises a water miscible washing compound.